Liposomes are vesicular sacs similar to tiny cells, composed by durable lipid bilayer membranes that separate an internal aqueous volume from the external medium. Water-soluble drugs can be encapsulated in the internal compartments, while water-insoluble drugs can be incorporated in the hydrophobic region of the membrane.

Argentine Scientists have developed an effective drug delivery system by grafting polymer groups to the liposome surface. It is used a hydrophilic polymer, methoxypolyethylene glycol (mPEG), and the critical design features of the PEG-liposome include the following:

- Increases in vivo liposome stability, reduces MPS uptake with long plasma residence times.
- Low permeability lipid matrix and carefully selected intraliposomal aqueous composition that provides high drug loading and stable encapsulation.
- Average diameter of 100 nm: Large enough to carry a substantial drug payload, yet small enough to allow efficient extravasation through vascular endothelial defects in tumor tissues.

With Pegylated liposomes, passive tissue targeting contributes to tissue specificity of the treatment. The drug carrier accumulates in the interstitial fluid of the diseased tissue by exploiting the enhanced permeability and retention effect.
Once the liposomes have infiltrated the cancerous tissue, the subsequent release of the drug from the decomposing liposomes provides local exposure to the cytoxic agent.

The delivery of controlled release drug employs drug-encapsulating devices from which therapeutic agents may be released at controlled rates for long periods of time.

Polymeric microspheres are ideal vehicles for many controlled delivery applications due to their ability to encapsulate a variety of drugs, biocompatibility, high bioavailability and sustained drug release characteristics.

The method of producing sustained-release microspheres containing a biologically active substance from an W/O emulsion comprising an inner aqueous phase containing said biologically active substance and an external oil phase containing a biodegradable polymer, characterized in that microspheres formed on microencapsulation of said biologically active substance with said biodegradable polymer are heated at a temperature not lower than the glass transition temperature of said biodegradable polymer but not so high as to cause aggregation of the microspheres.

The Depot formulations are administered to the patient and then release their active pharmaceutical ingredient for days, weeks, or months. Depot formulations comprise biodegradable excipients, lactide/glycolide polymers, which control the rate of drug release.

The pegylation of proteins was developed for improving biomedical efficacy, physicochemical and pharmacokinetics properties, and to reduce the number of weekly injections used in the treatment. The process takes place by a chemical reaction that joins throw a covalent union a molecule of polymer of metoxipoliethilenglicol to the recombinant protein. The high molecular weight of PEG used, allows to reach therapeutic ideal properties.

Applicability and safety of this technology have been proven by use of various PEGylated pharmaceuticals for many years. It is expected that PEGylation, as the most established technology for extension of drug residence in the body, will play an important role in the next generation therapeutics, such as peptides, protein, which due to their diminished molecular size need half-life extension.

This novel technology encapsulates different drugs within Nanomicelles formed with Gangliosides GM1.

- A great depth of tissue penetration for target drugs.
- Inner lipophilic core (ceramide) while the surface is hydrophilic (sugar)
- Suitable to solubilize lipophilic drugs as Paclitaxel and also remaining stable during several dilutions.
- Less toxicity in comparison with reference nano medicines.
- Expected better efficacy.
- Ability of self-assembly.
- Extremely low critical micelle concentration.
- Smaller size in comparison with liposomes (usually within 5-15 nm).
- Spontaneous loading of hydrophobic drugs.